DESCRIPTION (Applicant's Description): The Postgraduate Program in Radiological Science provides recent doctoral graduates in physics, chemistry, engineering, mathematics or in allied disciplines with additional training and experience in the field of radiological science. A rationale for the program is the growing need for basic scientists with training in medical and biological imaging, fields which are assuming increased importance in medical practice and research. The program is designed to provide a two year training experience and includes courses, tutorials and participation in research seminars and laboratory meetings in addition to active participation in research projects. Training is conducted in the environment of a major medical center whose physical setting, intellectual resources and research activities provide an exciting milieu for scientists in training. The academic element of the training is facilitated by the affiliations of the Massachusetts General Hospital with the Harvard Medical School, Harvard School of Public Health and the Health Sciences and Technology Program operated jointly by Harvard and MIT. Research opportunities currently exist in the areas of nuclear magnetic resonance imaging, functional MRI, chemistry of NMR contrast agents, positron emission tomography, quantitative imaging and kinetic modeling and radiopharmaceutical chemistry.